Which organ is inserted into the vagina during intercourse?

During intercourse, the penis is the organ that is inserted into the vagina. This action is a fundamental aspect of sexual reproduction in humans, allowing for the possibility of sperm reaching the female reproductive system. The penis is specially adapted for this function, featuring structures that facilitate penetration and the delivery of sperm during ejaculation.

The other options, while related to the reproductive system, do not serve this specific purpose. The uterus is a muscular organ that houses and nourishes a developing fetus, but it is not involved in the direct act of intercourse. The ovaries are responsible for producing eggs and hormones, playing a crucial role in the female reproductive cycle, but again, they do not have a direct role in the act of intercourse. The scrotum, which holds the testicles, is part of the male reproductive system for sperm production and hormone regulation, but it does not enter the vagina during sexual activity. Therefore, the penis is the only organ listed that functions in this specific way during intercourse.